Unplugged activity updates
- Support new lesson plans, pairs of links to html and pdf documents
- Show lesson plan html in an iframe
- Move videos to use specified keys rather than assumed the same as unplugged level key
- Add first course's unplugged levels
Hide lesson plans and PDF buttons when user is a logged-in student
- Add tests for lesson plan hiding
Add new unplugged activities
Add crowdsourcing lesson plan
Merge pull request #1007 from code-dot-org/unplugged_updates

Unplugged activity updates